Fluid meter



March 21, 1944. P. LANHAM FLUID METER Filed Dec. 15, 1959 3 Sheets-Sheetl will.

March 21, 1944. P. L ANHAM l 2,344,512

FLUID METER Filed Dec. l5, 1959 3 Sheets-Sheet 2 March 21, 1944.` Y P.LANHAM 2,344,512

' FLUID 'METER` Filed Dec. 15, 1939 3 Sheets-Sheet 5 m MC@ Patented Mar.2l, 1944 UNITED s'n-x'rizs PATENT OFFICE- Apmieauoa December is; No.309,4sc

35 Claims.

This invention relates to meters and more particularly to improvementsin meters relating to measurements with respect to iiuid flow wherebyvarious uid flow rates and quantities may be indicated and recorded aswell as integrated and transmitted with a high degree of precision. Theinstant application is thus directed to equipment similar in somerespects to that shown and claimed in my Patent No. 1,951,797

` of March 20, 1934, and others but more especially improvements,variations and simplifications whereby such precision measurements maybe obtained.

` In previous meters heretofore employed for measuring fluid flow,pressures, differential pressures and the like, the use of mercurylevels or columns with indicating devices responsive to variations inmercury levels has resulted in certain inherent difllculties andinaccuracies when a contact member (mechanical or electrical) vis usedto detect the mercury level although such contact methods have resultedin a higher degree of accuracy than other meth'ods. Whether themeasurement is indicated at the time of contacting the mercury surface(closing of an electric circuit), or at the time the contact leaves themercury surface (breaking of the electric circuit), deformation of themercury surface, temperature variations causing variation of the meterparts with respect to each other as well as other factors, al1contribute to prevent the obtaining of precision measurements. Meteringby square root cams and by versed sine methods have been attemptedemploying modifying means in order to secure measurements of quantitieswhich vary as the square root of another quantity in order to approachthe true square root or parabolic measurements; such meters not onlyrequire corrective means but require very complicated mechanisms inorder to approach measurements in a low order of precision.

The primary object of this invention therefore is to provide a newsimplified type of meter which will overcome the aforementioneddiiilculties and will give measurements throughout the entire range ofthe instrument with a high dev gree of precision. The extremely highdegree of precision measurements obtained by meters in accordance withmy present. invention is dependent upon the cooperation of severalfactors in order to overcome the difficulties mentioned,

among which may be mentioned;

An improved precision contact to read on break instead of make. Thisconsists of a. contact tip which is constantly coated, plated orimpregnated with material of the electrically conductive iluid withwhich the contact cooperates.

With a mercury column, the addition of a contact element having anamalgamated contact tip has been found to give an unexpectedly highdegree of precision rendering accurate and consistent measurements ofvariations of mercury levels of extremely small magnitude, in the orderof $10000 inch and less in lower ranges of the instrument and naturallyof a consistently high degree of precision in the upper ranges. Foulingof the conductive fluid column and/ or constantly coated contact tip ispreventedby maintaining a preservative fluid over the conductive fluidco1umn,-for a mercury column and a cooperating amalgamated contact tip Ihave found that glycerine, chloroform, methyl salicylate and otherfluids having the property of preserving and protecting mercury andamalgamated contacts operate as a sealing means with a high degree ofsatisfaction.

Improvement of the return of the electrically conductive'iiuid column tozero or the correct level responsive to the quantity being measured.

.In mercury columns which fluctuate due to varying forces which arebeing measured there are certain lagsA in the return of the mercury tothe corresponding levels; on a rising column of mercury the meniscus isdifferent from that on a falling column. Numerous other defects withrespect to this conductive column which introduce errorsvwhich aredetrimental in precision metering are corrected in accordance with myinvention by improving the consisncy of the column and the meniscus ofthe measuring level of the mercury as will be more fully set forthhereinafter. In measuring with a break contact inconsistencies due tolag and variations in the meniscus are further overcome by alwaysbreaking contact with a falling column by securing a plunger or mercurydisplacer to the contact rod so as to effect by lits withdrawal with thecontact tip, a falling of the mercury column at the time of the break ofcontact therewith. `the taking of a measurement this plunger may be madeto lock the mercury against movement in the measuring column and rangetube to prevent surges of the mercury at the instant the circuit isbroken at the contact tip. Further variations in mercury levels due toexpansion and y contraction by temperature variations of the vicepositioned preferably on the contact carrying'rod adjacent to theelectrically conductive column.

An improved method and arrangement for extraction of the square root ofthe differentials in height of the fluid column whereby, in taking tiowmeasurements, permitting iiow indications to be proportional to the iiowinstead of to the square of the iiow. While this has been attempted withsome degree of accuracy with cams and by versed sine means, the latterre quires corrective means, and both o! these methods are notsusceptible of precision construction as they are dependent upon suchcorrective means as to complicate their construction and they still failto produce precision measurements. In accordance with the presentinvention these faults have been overcome by providing a pair ofcooperating levers (or their equivalents) [or driving the contactelement, or otherwise to be driven in accordance with the position ofthe contact or mercury level responsive means, which )evers are soproportioned as to extract the square root with precision throughout therange of the instrument. These levers at the same time provide means forchanging over from the rectilinear movement of the mercury to theoscillatory movement which is convenient for recording and integratingmeters.

' Meters incorporating these improvements have the advantage ofproducing precision measurements at the same time employing fluidcolumns of small cross-sectional areas and with small movements of theiiuid columns thus requiring only a small quantity of mercury.

Further objects, details and advantages of the invention and methods ofoperation will be more fully set forth in the following speciaauon inconjunction with the accompanying drawings and claims hereinafter.

In the drawings:

Figure 1 is a diagrammatic vertical sectional view of a meter inaccordance with the invention.

Figure 2 is a vertical sectional view of the meter showing the left sideof the operating mechanism illustrated in Figure 1.

Figure 3 is a wiring diagram of the control circuits of the meter.

Figure 4 is a supplemental wiring diagram illustratinr,r a manner ofemploying the meter as a transmitter for telemetering.

Figure 5 is a detail diagram of the operating levers illustrated inFigure 1 showing the members in an intermediate position and a geareddriving connection between the operating levers of the meter and anindicator or recordng pen arm thereof.

Figure 6 is a detail diagram of operating levers in the same relativeposition as illustrated in Figure 5 but showing an equivalent lever inconnection with a link connection instead of a pair of engaging rollersproviding the connection.

Figure 7 is an enlarged detail view of a portion of the contact chambershowing the relation of elements therein adjacent to the mercury surfacejust prior to the breaking of contact with the detector members.

`Figure!! is a detail view of a iioat with a mercury well adapted to becarried on mercury, oil or other fluid which may be employed to respondto quantity variations, which float is adapted for cooperation with acontact rod and meter as shown in Figure i.

Figure 9 is a detail view of a modiiied type oi contact rod and itsconnection with the operating mechanism, and

Figure 10 is a vertical sectional view of an improved mechanical type ofmeter with square root levers applied thereto in accordance with theinvention.

Referring to the drawings the meterin accordance with this invention ingeneral comprises a detector contact member which detects the movementsof a fluid 2 the movements of which Vare responsive to variations inquantities to be measured, more particularly to pressures and/or iiow ofliquid of gaseous fluids. Contact member comprises a reciprocablecontact rod i, the upper end 3 of which is connected with operatingmechanism 4 for reciprocabiy driving the contact member and operating apen arm i5 so as 'to record on a driven chart the desired function of`the :movement of fluid 2, in iiow measurements extracting thesquare-root of the rises in height of iiuid 2 so that the degree towhich the recording pen is moved and o, record marie thereby is directlyproportional to the :dow instead of `the square oi the iiow, orlogarithmic. 'While the pen arm may be arranged for lineal or fine linerecording if desired, as disclosed in some of my previous patents,1,325,747 of December 30, 1:2319, and 1,935,508 of November 14, 1933,ior example, an ordinate plotting arrangement operating at timedintervals has the advantage that the pen arm moving means is adapted `tooperate an integrator directly and aiso when this pen arm moving meansis operated to produce an ordinate timed in proportion to the iiow themeter is f Aparticularly adapted as a transmitter for telelevels offluid 2 by contact member i detalls with respect thereto will be i'ullyset forth.

In order to measure differential pressures :Huid 2, mercury, oil or anyother desired fluid, preierably mercury which is an electricallyconductive fluid and has been most practical in measuring water, steamand other iuids, is placed in a manometer 'i comprising a contactchamber or measuring tube 8, and a range tube which is o! a selected orexchangeable size wherchy the percentage of mercury movement affectingregictration of 'the meter may he varied to suit the instal lation. Eachoil' these tubes is of uniform cross section for use with operatingmechanism il for extracting the square root of rises in 'height of themercury; they may he of equal size, or :for low flow measurements ahigher percentage in the contact side is desirable, whereas for a highow a smaller percentage in the contact side is necessary, as isrecognized in flow metering practice. Manometer 1 is provided withdifferential pressure connection pipes indicated as High pressureconnected with range tube 5 and the pipe Low pressure communicates withmeasuring tube B, being connected with a meter housing comprising apressure chamber i5.

In describing lthe meter, a one inch rise of mercury or other fluid 2 inthe contact tube B for a range on chart 6 corresponds with the iiguresand measurements set forth, although other mercury heights are employedwith the proper ascetic corresponding proportional measurements as willbe explained.

Tubes 8 and 9 communicate by means of an improved connection pipe I0,and among other improvements in this manometer is a fluid level adjusterIl comprising an external adjustable set screw I2 having a fluid tightpacking I3 which for convenience is positioned in connection pipe .levelin the' instrument as indicated at Il in the contact tube 8, or theadjustment or initial calibration may be made at any desired percentageof range. For example, under such a balanced condition of pressures inthe manometer, an artiilcial deflection of 5% or 10% -of range by thepen arm or indicator may be produced by giving the contact member a-nartificial added length ci .0025" or .01," which is identical in effectto raising the mercury level-by the same amounts respectively. iWhile'adjustable fluid displacer II may be calibrated as a micrometer toindicate differential adjustments of the mercury level (for a givenratio of range tube 9. size to that of the measuring tubeA 8) for theproper level at zero, or any other range of the meter, since the setscrew I2 is operable to change thelevel of fluid 2 suificient foradjustmentv purposes by infinitesimal amounts, due to variations in thetube ratios and other factors, the artificial added length which may begiven to contact rod l facilitates the calibration and is moresatisfactory in creating such an artificial deflection. If thedeflection were created by the adjustable displacer, it would beessential afterwards to actually change the fluid level again by meansof set screw Il to bring the mercury back to the corresponding levelinstead of merely removing a Calibrating shim.

As will be set forth, the meter is arranged to give the contact memberan adjustable plunge ranging up to about 1/8" below the zero level.

The added length for calibration purposes is conveniently accomplishedby means of shim l5 having the required thickness to producesuch acali-l bration deflection. When the operating mechanism 4 is mountedwithin the pressure chamber I6 this shim l5 is so positioned within thecasing that it may be inserted between roller members I1 and I8 of theoperating mechanism while they are separated during thebelow zeroplunge, and thus the zero level of the mercury may be adjusted so thatthe pen arm or indicator will show .the percentage deflectionrepresented by the thickness of the shim. The thickness of the shim mustbe accurate or necessary tolerances'in the deflection made to accountfor any variations from the required thickness since a flow onlysufficient to raise the level of fluid 2, .0001 corresponds to a 1%scale deflection. Shim I5 is connected with shaft I9 which in turn isoperated by means of a handle on the outside of casingr I6 for insertingit between the rollers and withdrawing it. To facilitate in makingadjustments, the pressure chamber may be of transparentmaterial in thezone of operating'mechanism 4 but as shown in'Figure 2 an inspectionhole with a transparent cover member Ila is provided for inspecting thelever mechanism while in operation. This is located where it will be ofgreatest value for adjustment, as at zero or any desired percentage ofrange.

In setting up the meter initial adjustments of the contact rod I may bemade in the connection of its upper end I with the meter operatingmechanism I. This connection comprises a differentially threaded hollowscrew 2| having a set of internal threads which receive the threadedupper end 3 of contact r'od I and an external set of4 threads of adifferent pitch from said internal threads, which external threads screwinto the lower endV of the contact raising and lowering elongate frame22 of the operating mechanism 4. It will be noted that contact rod Iextends through a guide 23 which may be a stuffing box in the event theoperating mechanism 4 is not encased in a pressure chamber and in theabsence of the casing I6 this connecting screw provides a highlysatisfactory means for adjusting contactA rod I so that its tip 24 is atthezero or other range level of fluid 2 although both adjustments incooperation with leach other are of material aid in setting up theinstrument for operation.

For precision in the operation of the meter the zero level is highlyimportant but in the use of mercury particularly other factors have tobe considered. The tube of the contact chamber 8 is preferably made ofglass or other non-deformprotruding outer wall of the float,

able insulating material'and in practice a measuring tube having a boreof 1*/8 diameter and 4" long is suitable in a meter having theproportions as herein particularly described. Mercury in this chamberrises from the zero level in response to pressure differentials andfalls correspondingly in the range chamber 9. Range tube 9 and connection pipe I0 are made of metal.

internally amalgamated; for this purpose copper has'been foundsatisfactory, the amalgam penetrates to a slight depth but does notdestroy the copper tube. Mercury in the manometer bonds with theamalgamated metal surfacesi and excludes uids above the mercury in therange tube from being trapped and thereby displacing mercury (which ishighly important particularly at lower ranges of the meter). Theamalgamated passageway also stabilizes the meniscus form, minimizingmenlscusvdiilerences on,rising and falling columns.

The meniscus form in the measuring chamber 8 is further improved bymeans of an amalgamated float 25 which functions to flatten andstabilize the mercury meniscus. For this purpose the float consists of asmall thin annular member amalgamated on its bottom, bore and outer sidewalls, but not on its upper surface which may be covered with aprotective coating such as lacquer or any Suitable non-amalgamable-material. This oat rides centrally on the mercury column and its boreprovides a passageway through which contact rod I and tip 24 will passfreely. Besides being maintained centrally by th mercury-meniscus thisamalgamater float has been found to bond with the mercury and follow hemercury accurately so as to maintain a uniform meniscus. The amalgamatedfioat, as illustrated en an enlarged scale in Figure '7, has theproperty of changing the meniscus form, between tlie float and thecontainer tube the mercury hugs the tube more closely for-ming a doubleor reverse curve, downward around the walls of the glass tube surfaceand upward around the while in the center the mercury surface ismaintained in a slightly depressed level which is uniform under alloperating conditions of the meter.

Further in order to avoid mercury level variations due to changes of themeniscus on rising and falling columns contact rod I is provided with adisplacer 26 comprising a perforated support 2l secured on contact rod Iin a suitable manner such as a set screw 28. 'I'his support may be oi'metal, hard rubber, Bakelite or other suitable material and is formedwith a. sloping or conical upper wall 29 whereby fluids will not beretained thereby. As a displacing element a thin walled tube IIJ securedto support 29 and having a strainless fit in the glass measuring tube lhas proven satisfactory although this form is obviously susceptible tomodification. Tube' extends from support at least the length of themaximum mercury elevations and has the greater portion of its side wallscut away above its bottom edge so as to provide substantially adisplacer ring supported by upwardly extending flns; with such astructure the vfalling of the mercury level takes place substantially atthe time the ring` portion is withdrawn from the mercury column.l

'I'he displacer is mounted on contact rod I so that contact tip 24 issubstantially in the plane of the lower edge of the displacer andthereby the displacer co-functions with the contact tip mounting toeffect a recession or falling of the liquid level just prior to orduring the withdrawal of contact tip 24 from the mrecury, fluid 2.

In order to prevent surges of the fluid column as may occur when thequantity being measured is rapidly fluctuating, a self closing valve 3lis provided in the bottom of measuring tube 8 which closes during thetaking of measurements and opens subsequent to the completion ofmeasuring strokes. This valve coacts with contact rod I, a perforatedoperating cup 32 being shown with its upper edges for engagement by thedisplacer element 30 for depressing the valve to open position at thetime contact rod is at .the lower portion of its downward stroke. As thecontact rod I rises on its upward movement toward the zero level of themercury valve 3| gradually approaches closed position so thatwhen`contact tip 24 reaches the zero level the valve is closed by itsoperating spring 33 suillciently to prevent surges in the mercurycolumns in tubes 8 and 9 of the manometer. I

Thermal expansion and contraction of the mercury and other meter partsis compensated for by means of a compensating element 34 as a part ofthe contact tip driving member, contact rod I, and tip 24 to raise andlower the contact tip in consonance with the rise and fall of themercury and other changes in adjustments due to expansion andcontraction produced by temperature; it is preferably close to themercury so as to receive the same effects. A satisfactory constructionof this compensator consists in forming one section of rod I with aterminal collar 35 and the other section with a sleeve 36 enveloping 'anelongated member such as a tube 31 having a relatively highercoeillcient of thermal expansion as compared with the other elementsincluding rod I, part of which it engages. An inwardly extendingshoulder 38 at the end of the sleeve encloses member 31 and maintainsthe parts assembled.

For precision measurements with respect to such an improved arrangementfor obtaining accurate mercury levels it is essential to have a detectorelement which will operate with precision. The usual forms of contactpoints have proven unsatisfactory in measuring break contacts. Inaccordance with this invention, therefore, contact rod I is providedwith an amalgamated contact tip 24. As best shown in Figure 7 this tipis formed for convenience by inserting a small diameter rod or wire ofamalgamable material 39 in a member, rod l of non-amalgamable materialor otherwise supporting and shielding the amalgamable material so thatthe surface exposed to the mercury is thereby controlled as to lengthand dia-meter (or area) for best results. It is preferable to amalgamateand expose to the mercury only the lower surface.

Good results have been obtained using an insert in diameter slightlyrounded at the tip and practically flush with a stainless steelshielding. Hard rubber and Bakelite have also been found effective asshielding. As shown, the shielding constituting'the lower part of rod I,is of tapered formation surrounding the insert and is convenientlyformed of 1/ diameter rod contact tip.

. mercury, fluid 2, levels by break contacts are i.

Heretofore contacts with the mercury have been made under water butprecision detection of the obtained in the manner above explained and inaccordance with my discoveries such detection of the differential levelsis possible with accuracy heretofore unknown. Even though very smallcurrents are employed in connection with such contacts with mercuryunder water, water electrolizes, mercury oxidizes and even anamalgamated contact tip oxidizes; salts in water are deposited so thatthe mercury and contact tip become fouled and corroded, and such defectresults in erratic indications or recordings. Similarly it has beenfound that if transformer or like oil is used, a black deposit forms,possibly due to carbonization of oil caused by spark. On the contrary,however, I have discovered that glycerine (which is heavier than water)prevents such fouling due to oxidization and carbonization; chloroformand methyl salicylate are also found to be advantageous in protectingmercury and amalgamated surfaces since they are heavier than and do notmix with water and have inherent physical, chemical or electricalproperties of benefit In employing the meter for measuring water flow,as shown in Figure 1, glycerine which is found preferable of the variousfluids mentioned. is placed over the mercury to a depth slightly inexcess of the maximum mercury rise in measuring tube 8, as indicatedfrom mercury level I4 to the level 4I), to ride on the mercury as itrises and falls in the tube. An intermediate fluid over the glycerineand under the water, as indicated between levels 40 and 4I, is necessaryto prevent water, above level 4| up to level 42 which is substantiallythe level of the low pressure pipe connection for the meter, fromcontacting the glycerine. This fluid can be either chloroform or carbontetra-chloride mixed with gasolene or similar fluid to give the requiredspecific gravity to maintain the fluid in the intermediate position;methyl salicylate has the proper specific gravity without mixing withother fluids; various other fluids or fluid mixtures obviously may beused for the same purpose. ment which normally enter the meter with theDirt and rust sedigas and similar foreign matterwhich would normallysettle on the mercury are retained in suspension either at the top ofthe glycerine level or at the top of the sealing fluid level.

Abovethe water level 42 the pressure chamber or meter housing I isfilled with oil which is supported n the water in a manner to protectand lubricate the operating mechanism 4; in gas or airflow meters thisoil can rest directly on top of the glycerine provided the pressureconnection is above the oil level. y t

As pointed out mercury has been found to be most practical as amanometer fluid, fluid 2 for a variable contact element; however in someinstances it is desirable to employ other fluids such as acids or acidmixtures and the like which are and in some instances a solid membermovable in response to variations of pressures or quantities to bemeasured. l

Numerous adaptations for such variations will appear as falling withinthe scope of this invention. `By way of example a solid body such as afloat 43 as shown in Figure 8, having a well 44 therein of sufficientdepth for a full range of the meter (about 11,41" for a l range meter)which well may be filled with mercury may be employed with eitherelectrically conductive or insulating fluids and even in mercury, whichfloats, of course are constructed of materials of proper lng memberswill be maintained until the instant frame member 50 has been moved bythe other parts of the operating mechanism 4 sufficiently to produce abreak of contact therebetween.

Referring to Figure l, it will be seen that pen arm 5 or indicator isemployed with a chart 6 which is shown as a fragment of a circular chartand this chart divided into arcs or circles indexed in percen isdesirable in recording meters. Recordings of weight suitable for floatsin the fluids in which theyy are employed. Such a float when its well isfilled with` mercury will maintain a central meniscus form of thecharacter referred to in connection with float 25, particularly if it isamalga-mated, and in a mercury column it will behave in very much thesame manner as float Y 25. 'I'his float 43 is suitable for use witheither` conductive or nonconductive fluids, and in the event anonconductive fluid is used, in addition to a contact tip 24,amalgamated, .or saturated with the conductive fluid used in the well, aconductor member 45 may be carried by contact' rod I but insulatedtherefrom for the purpose of providing an electrical circuit connectiontherewith. This conductor extends beyond tip 24 so as to be maintainedin communication with the fluid in the well at all times or at leastuntil contact tip 24 breaks circuit with the fluid.

Again in case a tip 45 of a contact rod 41 is to engage a solid member48 which likewise constitutes a variable contact element as illustratedin Figure 9 this rod 41 which is similar in all other respectstocontactrod I, is provided with a thrust member such -as a weighted ball 49 atits upper end. The operating mechanism 4 is provided with a slightlymodified elongate frame 50 apertured at its lower end for slidinglyreceiving rod 41 and provided with a longitudinal guide way 5I inwhich'weight 49' may slide. It will be noted that in this arrangementthe adjustment may be such as to provide a positive contact similar tothe below zero plunge" of contact rod tip 24 in mercury,-that is whenframe 50 is in its lowermost position the supporting lower end of theguide is spaced slightly (1A;) below weight 49 so that it is free tobear or force rod 41 with its contact tip 46 into engagement with thecontact surface of member 48 with sumcient force to insure properengagement therewith. In the event of a movement of members 40 suchengagement of the contactof flow instead of square of the flow by nowmeters is particularly desirable for integrating as well as intelemetering practice.

The indicator or pen arm 5 is shown at the bottom of the scale, 0%, inthe solid line position with the operating mechanism 4 and 'contact rodI at bottom stroke position and in dotted lines the pen arm or indicatoris shown at 100% scale range,- and parts of the operating mechanism 4are indicated in dotted lines in this corresponding position. The sweepof the indicating or pen arm 5 is 45 on chart B, as diagrammaticallyillustrated, upon which angle computations for measuremnts of the levermechanism hereinafter described, are based. Since in practice somecharts are formed for a half of that angle of Irecording pen arm sweep,as illustrated in Figure 5, the| sweep of the pen arm 5 may be reducedaccordingly` by means of a reduction gear transmission comprising gears52 and 53 for driving the pen through the smaller angle for operating onthe upper part of the circular chart instead of the lower part asindicated in connection with chart 6 in Figure l, with the sameproportions of operating mechanism 4 which has advantages as willpresently be described. The larger angle has an advantage in that asecond indicator or pen arm 5a, may be driven directly so as to plot lowrange deflections on another portion of the same chart and for such lowscale deections the angle may be multiplied by gearing in a similarmanner for plotting still longer ordinates in recordings by the meter.0f course, the sweep of the pen arm for full range on the chart througha particular angular displacement of the upper lever may be accomplishedby selecting the length of the pen greater in length than itsreciprocatory range in frame 22 which engage an oscillating sleeve 55constituting the driving member for the in- .dicator or pen arm 5.

Roller element I1 of the operating lever mechanism is mounted on a pivot56 secured or journaled in frame 22 so as to move upwardly anddownwardly therewith. The roller element I8, which coacts with roller I1and together constitute one of the operating levers during a measuringstroke of the meter is mounted on a pivot 51 mounted in an oscillatorybell crank member 58 which ls integrally :connected with sleeve 55 andconstitutes the other cooperating lever element of the lever operatingmechanism.

It will be noted that rollers I1 and I8 whic ges from 0% tol00%whichcoact in constituting one ot the operating levers. are truecircles, and, for convenience of the same size; however, by observingFigure 6 and comparing with Figure it will be seen that a lever element59 can be and may be substituted for these roller members; it will benoted that the lever mechanism is in the same intermediate drivingposition (approximately 60% of range) and that the proportionate lengthsA and B of the lever arms are identical as to lengths which function toextract the square root of the fluid heights as will be explainedhereinafter. For convenience the upper and lower lever members will bereferred to as levers A and B respectively.

Referring to Figure l again, it is sometimes desirable to hold one of throllers I1 or I8 against turning and for thisl purpose a roller lockingelement 60 is shown holding roller I8 in a non-rotatable position. Inthis way the other roller I1 coacts with the same surface of roller I8in the manner of a cam, and while for the purpose of extracting thesquare root this surface is truly circular. The arrangement provides fora cam otherwise shaped whereby other functions than the square root maybe obtained in the operation of the meter, such variations being ofimportance in particular applications of the meter, notwithstanding thefact that in accordance with the principal feature of this invention isthe provision of coacting levers bearing a constant relationship witheach other which will extract the square .root with mathematicalexactness without employing correcting elements and operate in a meterwith such precision as has been impossible heretofore.

For extracting the square root of varying heights of the level of fluid2 in, measuring tube 8 for a rise of Vl" and an indicator swingr of 15levers A and B having lengths, for illustrative purposes, of 1.455" forA and 1.196" for B. Levers of such lengths have been employed andoperate well within the range of tolerance for metering practicealthough for other ranges and angles levers or other lengths bearing thesame ratio as to length with respect to each other operate in a similarmanner for indicating and recording flow measurements and with even ahigher degree of precision with levers of selected lengths.

It is to be noted that lever A swings upward with equal angularincrements ior equal flow range deflections but lever B following leverA swings outward varying increments; each of these levers takes up avarying proportion of the total displacements of the contact tip.Further noting that these displacements angles by the upper longer leverA are proportional, it is pointed out that their increments ofdisplacement are less than half o! the total required displacement andare functions of the versed sines of the` angles of displacement of theupper lever member but the greater increments of displacements by thelower lever are of a continuously varying character since they arefunctions of the versed sines of the varying angles.

Versed sine displacements do follow the square root with quite closeprecision up to a ten degree angle after which the errors increase toprohibi tive values rapidly. Therefore they 1re only useful through verysmall displacemnt angles for metering practices without employing formsof correcting means which in themselves are apt to introduce errorswhich detract from the accuracy arm 63 integral therewith having a ofthe instrument or meter and are altogether too faulty for use in aprecision instrument.

It is due to the above limitation in the versed sine operation that Ihave evolved the new principal of a pair of levers in, togglearrangement and so proportioned as to extract the square rootmechanically and with such exactness for the operation of meters with adefinitely higher degree of precision. In practice it has been foundthat the square root levers having the illustrative dimensions set forthoperate in recording flows-with exactness up to and above the range ofthe chart which corresponds to an angle greater than 40 of the A lever,and with only a slight error well within meter tolerances at range. At90% and below. the iiow error is negligible and does not appear in sofar as meter indications and recordings are concerned.

It is to be further noted that the above measurements are based for arange swing oi' 4T with a displacement of one inch in setting forth anexample which is accommodated to present practices with one of the usualforms of clock operated meter charts, with an angle ci 221/2, beingadapted for the same by reduction gears as shown in Figure 5. Suchreduction gears could be omitted in operating with the same levers byemploying a displacement of .25" as a maximum (50% of range) instead orl", or for a l displacement the dimensions ci' the levers would have tobe proportionately increased, each four times the lengths stated.However, in order to conserve .space it is erahl` to employ `the shorterlevers which regni. lcs e and thereby provide ior a more compat` meterunit Similarly the displacement ant l lor .lull range as well thedimensions oi lever elements may varied. but in. all: instancrtheproportionate lengths oi" the levers reina f a constant. These leversmay be operated to raise lower the contacting element as may be requiredto adapt them to 'the broader applications or other applications astypied in Figure l0. The longer lever is always angularly displacedproper-- tional to the square root of lineal movement of the remote endof the shorter lever.

Levers A and B being toggle lovers, drive by or through the upper leverA is convenient. Ac cordingly lever .A of operating mechanism l as shownin Figure l is arranged to ce driven; bell crank Eil comprising thislever an arm 8| through which oscillatory movements are lmpartedthereto. A driving shaft E2 is jcurnaled in oscillatory sleeve 55 and isprovided with an contact roller member Sil on its outer ond whichadapted to engage a Contact surface E5 on bell crank lever arm 6I toswing it for a forward or measuring stroke of the meter'.

Lever arm El is also formed with an abutment surface 66 which engages astop ill which is positioned or may be adjusted so that when it isengaged by the abutment surface t6 the pivotal axes or' levers A and Bwill be in alignment, that is, the centers oi driving shaft E2 andpivots 5l and 56 will all lie along the center line axis, designated 68,of contact rofl I and frame 22. A spring element 69 secured to lever armEI functions with a spring lll to return the lever to and maintain theparts in said relationship, with the frame 22 carrying contact rod Itensioned in an 'upward direction. Spring 1U is tensioned between anextension il of lever A of the bell crank lever and a lower portion offrame 22 to elevate the frame and contact rod I and maintain roller I1in engagement with roller I8 during a measuring stroke of the meter. Asa metering stroke progresses the` tensionl of spring 1l decreases butthe tension of spring 69 in- -creases and onlong strokes the tension ofthis spring is suillcient to overcome and release any reversing themotor driven shaft at the critical range recording points in meteringoperations.

As stated, lever element A, the bell crank 58 h an oscillatory strokethe length of swing of which is determined by the height of the mercury,fluid 2 in measuring tube 8, and as illustrated in Figure 1 for itsmaximum stroke for a full range recording on chart 6 (which its strokemovements determine) the roller element I8 is swung by the A leverelement of the bell crank from position III to position IV. Roller I8 isof course a part of the B lever element, roller I1 constituting thecoacting other part thereof during the measuring operations of themeter. Roller I1, however, is illustrated in three positions I, III, andIV of its upward movement for a full range recording on chart 6 and theroller 64 carried on arm B3 of drive shaft 62 is shown in fourpositions, I, II, III, IV for such a recording. It will be noted thatframe 22 has an ,upwardly extending cam portion 12 which is engaged'byroller 64 and so as to depress frame 22 and rod I so that its contacttip 24 has a below zero plunge, of about 54, or less.. The amount ofthis plunge is determined by the extent of swing of drive shaft 62 inpositioning roller 64 for position I which isdetermined by a stop 13which may .be adjustable and against which arm 53 abuts to determine thebelow zero plunge. During a measuring stroke driveshaft 62 swings roller54-in a clockwise direction as it moves from position I to position IIframe 22 and contact rod I rise and roller I1 rises from itscorresponding position I to position III in engagement with roller I8ready to coact therewith during the measuring stroke and contact tip 24is at its proper position for the fluid 2 zero level. In' order to'avoidconfusion, however, the parts below roller I1 are only shown in their jinitial position, with contact tip 24 in its below zero plungedposition. During the interval following movement of roller 64 fromposition II there is a zero pause when contact tip 24 remains at itszero level position until roller 64 reaches its position III incontacting engagement with contact surace 65 at which time the measuringstroke of the meter begins. During the further movement of roller 84,frame 22, contact rod I with its contact tip 24, and roller I1 rise as aunit, roller I1 moving upwardly from position III following the outwardswinging movement of roller I8 from the initial position III thereof forthe duration of the stroke as determined by the elevation of the fluid 2in the measuring column; the corresponding full scale range positions ofrollers I1 and I8 contact roller 84 are each indicated IV.

Referring to Figure 6 it will be seen that the arrangement employing alink type of lever element 58 will function in the identical manner, thelever being formed at one of its ends with an elongated slot 14 toprovide for the .below zero plunge of contact tip 24. ,A spring 15between the pivots 56 and 51 insures the proper coaction of the leveroperating elements during a measuring stroke. f

As disclosed both arrangements provide for a below zero plunge of thecontact tip. However in the event it is :desired to operate the meterwith the contact detector element moving from indicator maximum or abovemaximum (a movement oil scale corresponding to the below zero plunge)down to the fluid level, the mechanism can be materially simplified asthe cam 12 is not required and can be omitted, likewise no relativemovement between pivots 56 and 51 (in Figures .1, 2, 5 and-"6) isrequired and thus the B lever element can be 'secured between thesepivots thereby omitting lostmotion, and in Figure 6 'closed in my Patent1,951,797;

slot 14 and spring 1l.

As shown in Figure 2 the indicator or pen arm driving sleeve 55 of bellcrank lever 58 extends outwardly through a stufling box or journal 16preferably grease packed, and outside of the casing I6 is drivinglyconnected with the indicator or pen arm 5 in the manner set forth. Inaddition to the indicator, this sleeve having oscillatory movementproportional to the flow, as measured through the square root levers, isparticularly adapted for direct operation of flow integrators and suchan integrator is diagrammatically represented at 11. This 4integratormay be of the one way clutch type as fully disits simplified adaptationto my present meter isclearly apparent.

.Sleeve member 55 is preferably closed at its outerend to preventleakage or the necessity of a fluid tight packing around drive shaft 62if it were arranged to extend through this outer end of the sleeveinstead of being journaled therein as shown. Further, the other end ofdrive shaft might be extended rearwardly through casing I6 to be motordriven but preferably as shown it is journaled in a trunnion 18. Thisarrangement provides for the proper positioning of bell crank lever 58and the alignment of the two shaft members; drive shaft 82 and sleeve55, is maintained by the front journal 16 and rear trunnion 18 with theintermediate sleeve bearing arrangement between them.

Reciprocatory plunger type motors such as disclosed in some of mypatents referred to, the combination of a forward drive motor and areverse return motor and other types of drivers have proven highlysatisfactory for meters according to the present invention, butpreferably for the operation of drive shaft 62, since the power requiredis very small, as shown, a self starting synchronous motor indicated at19 may be employed. This motor is diagrammatically pictured as areversible Telechron type of motor, which is employed because of itsavailability but for metering a synchronous motor is not essential. Ingeneral this Telechron type of motor includes anarmature enclosed in anupwardly extending tubular casing engaged by a pair of field memberswith field windings 8| and 82 which are arranged for reverse operationsand will be termed up and fdown motors respectively. These parts areabove a substantially fluid tight casing 83 which houses reductiongearing for operating its drive shaft 84, in either direction inaccordance with the energization ci the eld winding selected, at a speedof 1 R. Pi M.

While such a motor is susceptible of operation within the uid chamberi6, motor 19 is shownv positioned above it with its shaft 84 extendingthrough a stuffing box B providing a journal which is preferably of thegrease packed type to reduce friction on the shalt extending into thechamber where it is drivingly connected with drive shaft 62. Thisdriving connection between shafts 84 and B2 is shown as comprising apair of gears 86 and B1 which are of the proper ratio to drive shaft E2,and the indicator or pen arm 5 at any desired speed. Although high orlow speeds of operation may be employed, of course as the speed isincreased the driving power also must increase. In practice a reductionto half speed,

l point shown elevated contact tip 24 to the zero V2 R. P. M. as aordedby gear 81 being twice the size of gear 8E, has given excellent resultsin ordinate plotting on a chart 6 by the pen arm 5.

The control system for operating the meter is diagrammaticallyillustrated in Figure 3 wherein the source of power supply is the usual60 cycles alternating current at 110 volts delivered to lines 88 and 89.These lines feed into a step down transformer' 9U for supplying a 10Wvoltage for operating a'relay 9| as controlled by a clock operatedcommutator 92, the clock mechanism of which also operates to drive thecircular chart E with, which the indicator or pen arm 5 cooperates inrecording. Alternately, as disclosed in several of my prior patents, alouT voltage direct current source as supplied by a few battery cellsmay be used in place of transformer Sil, but this transformerispreferable as it i'ound satisfactory in thearrangement as disclosed andhas the advantage that the necessity for a battery source is obviated.

The operating circuit for relay Bl ismfrom the low voltage source9.0,.by conductor 93 through the operating coil of relay 9i, conductor94, contact element 95 and segment 28 oi commutator 92, thence throughthe frame structure as represented by grounds 91 and 98 to contact rod Iand contact tip 24, through the mercury, fiuid 2 which is insulated fromthe frame structure but electrically connected by conductor 99 back tosource 9G. Commutator 9| is shown as rotating in a clock wise directionwith its segment 9S just having passed contact element 95 but relay 9|has been energized by the circuit as stated and its two armatures Illland |02 (shown for simplicity), being actuated and engaging' their innercontacts. Inner' contact of armature |62 is connected with conductor 94.When this armature which is grounded to the frame as represented at i03engages its inner contact it affords a parallel path to the frame andthis maintains the circuit closed after segment 96 has passed contactelement until contact tip 2d breaks contact with the mer cury, fluid 2.

When relay 9| is energized its armature lili is in engagement with itsinner contact shown connected with a conductor illu. alrniature ""lbeing connected by conductor Iii with line 1l power is applied therebyto conductor litri, through up field winding 8l of motor 1Q and thenceby conductor |06 to the other line 8S and thereby energizing motor 19 toeflect an upward movement of contact tip 24 through operating mechanism4.

As shown, the motor has been operating from the time the relay circuitwas made by clock con-- tact element 95 and segment t5 and has at theposition and 'roller I1 of the operating mechanism into engagement withroller I8 thereby placing them into coacting relation as B lever. Motor1l will continue the up drive until contact tip 24 is raised to thecontact breaking point with respect to the mercury uid 2, level which isshown as having a rise in measuring tube B.

At the instant of this break of contact of contact tip 24 and themercury, the circuit of the low voltage power source 90 for energizingrelay 9| is broken, relay 9| is deenergized, armatures |0| and |02thereof are withdrawn from their inner contacts breaking the circuitthrough the up field winding 8| of motor 19, immediately stopping andreversing the operation of the motor by relay armature lul being broughtinto engagement with its outer contact. The power from line 88 is thenby way of conductor |05, relay armature Il and outer contact thereof andconductor |81 connected therewith and a switch HIB in a closed conditionin conductor |01 through the down eld winding 82 of motor to conductor|08 and to the other line B8 to energize motor 19 to eiect a returnmovement of drive shaft E2.

At the time of break of contact tip 24 with iiuid 2, not only does motor19 stop and reverse, but the stopping is assisted by friction of theparts stuiling boxes, etc., and cooperation of springs 59 and 10,particularly the latter in which accumulated energy is stored as bellcrank lever 53 is swung during the operating stroke, and as motor 19 isoperated in the reverse direction to return drive shaft 52, its arm 63and roller |54 to initial. position, I, these springs Gil and 10cooperate in returning the elements of the operating mechanism to theirrespective initial positions and to give contact Lip 24 its below zeroplunge.

Armature ||l| of relay 9| having opened and engaged its outer contact toelect the reverse operation of motor 19 remains in this position untilsegment 96 of clock operated commutator 92 again engages contact elementB5 to energize relay 9| again to repeat the cycle at such intervals asmay be desired, the commutator being de signed with as many segments orto be driven at such speeds as may be required to effect the desiredduration of such intervals, In the meantime the down eld winding B2 ofmotor I9 Is energized so as to return drive shaft E2 until arm 63thereof engages stop 73 when motor 19 is stopped or stalled therebyuntil relay 9| is energized again which is entirely satisfactory.Although switch IUB can be arranged to be me` chanically opened afterarm 63 engages stop 13 if desired when ordinate plotting is arranged totake place at long intervals, in the case of motors such as set forth, Iprefer that switch Hi8 remain closed and allow down eld winding H2 toremain energized with the motor stalled for the time after its operationuntil. relay,1 9| is energized again.

This meter, being a power operated meter, is particularly adapted foroperating integrators as well indicating and recording devices, and islikewise operable as a telemetering transmitter i'or driving anyconventional type of power operated transmitter driven by sleeve in thesame manner as the indicator or pen arm 5 as shown in Figures l. and 2.It is also operable for transmitting signal current impulses in numberproportional to the indication or recording on the chart in the mannerpresently set forth, such im pulses being present due to the alternatingcurrent employed when the meter is provided with a synchronous electricdriving motor.

Operating the meter with such asynchronous motor 19 is advantageous inthat the ordinates plotted are of timed duration directly proportionalto the ilow and thus the meter employing such a synchronous type ofmotor is adaptable as a telemetering transmitter and for this purpose asynchronous type motor is essential for transmitting alternating currentimpulses which are in phase with the motor operating the meter. Figure 4diagrammatically illustrates a supplemental l0 circuit whereby theduration of ordinate plotting may be detected and electricallytransmitted. For this purpose contact surface 65 is electricallyinsulated 4from the remainder of bell crank 58 and provides anelectrical contact element with which contact roller 6I cooperates;contact roller 6I carried by drive shaft 62 is thereby conductivelyconnected with the metallic frame structure of the meter, but if desiredthis roller may also be carried in insulated relationship with respectto the other meter parts. Connections of the motor up winding 8| throughrelay armature IIII with lines 88 and 89 are the same as in Figure 3disclosing the meter operating system connections in full and in Figure4 connections for telemetering 25 by the meter are added. Theseconnections include-a conductor IUS connecting line 88 with contactroller 6I; a conductor IIB connected with contact surface 65 and aconductor I I I connected with conductor IM; these latter two conductorsIIIJ and III are transmission lines which lead from the meter to areceiver and operate to transmit timed current impulses the duration ofwhich are directly proportional to the flow being measured by the meter.It will be observed that the current for such timed current impulsesoriginates in the lines 88 and 89 which are supplied with the electricpower for the operation oi' the meter. When the-relay is energized itsarmature IUI engages the inner contact thereof thereby 40 connectingline 88 `with one of the telemetering' transmission conductors III atthe same instant the motor up winding 8l is energized and actuation ofthe meter operating mechanism 4 is initiated. At the time up motor haselevated contact tip 24 vto its zero level and contact roller 8l engagescontact surface 65, but 'not until the engagement of these-contactelements, line 89 is connected through conductors |09 and those engagingcontacts with the other telemetering transmission conductor III) and atthis instant both of these conductors III! and III are energized fortransmitting current impulses of timed periods and of durations or innumbers proportional to a function of the quantity measured over thelines to a receiver. This timed impulse is due to the fact that motor I9operating the meter operates at a synchronous speed and the lever arm Aof the square root levers is driven thereby so that the duration of itsswing is directly proportional to the function of the quantity beingmeasured which the angular swing of lever A indicates by the indicatoror recording pen arm 5. i

The duration of this impulse as well as the energization of winding BIfor driving motor 19 in its up direction is determined by the break ofcontact between contact tip 24 and fluid 2 which deenergizes the controlrelay so as to release its armatures and so that the circuit is brokenby armature IUI being withdrawn from its inner 70 contact.

By this arrangement these telemetering current impulses are of precisiontimed duration, .and at timed intervals as determined by the clockmechanism of the meter. The fact that the synchronous driving motor 18operates for an interval before the initiation oi' the telemeteringimpulse perfects the precision of the impulse duration since it givesthe motor a chance to start and come to an even synchronous speed beforethis impulse and the measuring stroke of the pen arm (lever A) areinitiated and thus the synchronous speed of the motor during thisportion of the complete meter strokeraising the contact tip from itszero plunge to zero and then the zero l pause, succeeded by themeasuring movement of lever A and recording pen arm.-

The meter employing a synchronous power driving motor for producingordinates of a precision ytimed duration isalso applicablefor'telemetering operations of modified forms. Noting particularly thatthe meter is operatedat timed intervals as well as the timing of theordinate plotting, the time intervals between such ordinate plotting;are also susceptible for transmission in telemetering and therebyvarious arrangements for transmitting telemetering currents or impulsesmay be resorted to.

In the arrangement as described, the indicator or pen arm is operated torecord ordinates which arrangement is preferable for numerous operationsby the meter as set forth. While the indicator or pen operatingmechanism can ybe arranged for ine line operation or recording, theplotting of ordinates hasnumerous advantages particularly for precisionrecordings in that the tip ends of the recorded ordinates determine theflow measurement with greatest precision exactly the square root of therise of the mercury in the measuring tube. The arrangement of parts isalso such that recording of the mercury level rising from zero in themeasuring tube of the manomi eter is preferable, that is with thepressure connection, or high pressurey connection with the range tubeinstead of with the measuring tube of the manometer; obviously howeverthe reverse of this operation is Acontemplated within the scope of thisinvention. In connection with such precision operation of the meter itis to be observed that the precision is made possible by several factorsincluding the improvement of the fluid column and its adjustment to thezero of the instrument operating mechanism, the precision break ofcontact between the mercury and the amalgamated contact tip, and theoperating mechanism for extracting the square root and the precision ofits operation.

,In Figure 10 a practical application of oper- A ating mechanism II2 forextracting the square root of mercury deflections in the oppositedirection is shown, that is with pressure applied through a pipeconnection inlet II3, into the measuring tube or chamber` I I4 of themeter and a low pressure connection IIS is made with its range tube IIB,with a pipe III providing a connection between the measuring chamber andlrange tube; altho this meter is also operable and has been operatedsatisfactorily with the higher pressure applied to the range tube. Thear-` rangement disclosed is a modification` and improvement over themechanical manograph disclosed in my Patent 1,935,508 of November 14,1933, and briefly one of the improvements consists in using a weight II8 which has the advantage over thearrangement disclosed in the pat-vent since in that arrangement as the line pressure changes loss of headthrough the valve seat varies and that in turn causes a slight change inthe valve opening even though there is no change in mercury level. Whilethe line pressure re- In general measuring chamber II4 and range tubewhich communicate by way of connecting pipe III comprise a manometerwhich contains the operating iiuid, mercury ||9 and a float |23 thereonin the measuring chamber. The measuring chamber and range tube are shownmounted on a suitable 'form of base |2| for supporting the meter in arigid, upright position. The range tube and connecting pipe elements inthis instance may be amalgamated as heretofore set forth and varyingtypes of range tubes or chambers may be employed. As shown range tube||3 is of smaller diameter than meas uring chamber ||4 and isparticularly adapted for the meter in operating under high pressurediiierentials with the smaller variations of mercury depressions in' themeasuring chamber-` that is, there may be a range of an inch to an inchand a half in the measuring chamber and in the range tube as much as afoot or more for operating under such high differential pressures. Theparts are illustrated in a position approaching full range oi' mecurydifferential in measuring chamber ||4 and range tube IIB.

Weight I |3 comprises a piston element which is reciprocabie in a pistonchamber |22 secured to and extending upwardly from the measuring chamberI|4. In effect, chambers ||4 and |22 are, combined, a measuring andpiston chamber. However, while thispiston could function as a sealingelement along the walls of chamber |22, in order to improve theoperation of the meter it is made freely slidable therein in a manner topermit fluid to pass between its outer surtace and the side walls of thepiston chamber. A sealing member |23 comprising a diaphragm isperipherally secured between the top edge of measuring chamber ||4 andthe lower edge of piston chamber I 22. A central guide tube ele ment |24extends centrally from diaphragm |23 to which it is secured by aclamping element |25 cooperating with a tube extension member |24aupwardly through a central bore in weight Ill, and guidingly terminatedin a reduced upper chamber |26. Weight IIB rests on clamping element |25and withtube element |24 and |2ta is movable as unitaryV piston element.

Tube |24 provides a guide housing for a rod valve element |21, which rodvalve element is heavy enough t`o overcome fluid pressures acting on ittending to maintain it in an elevated valve closing position. it islooselwguided in tube |24,

a collar |21a guiding its upper end and a re-4 duced lower end portionextending through a strainless guide |23 centering the lower end of thisrod and this lower reduced portion has a centering tip '|29 whichengages a cooperating recess |3| in the mercury float |20. Tube |24 isprovided at its lower end extension |24a with one or more lateralapertures |3| whereby a iluid passageway is provided from measuringchamber I|4 into tube |24 and along rod element |21 to the upper part ofthe tube. The

75 |33 to restore the balanced condition.

mains constant or variations are slight the met'el-` operatessatisfactorily but for precision measure' |24, Valve element |33 hasfluid passage therethrough affording communication from tube |24 to theupper part of bore |34 of head member |35, and from this bore fluid canpass through vone or more passages |38 into upper chamber |26; thencethe fluid maypass around the head member |35 along the outer side oitube |24 into piston chamber |22, also from upper chamber |2|y throughconductor pipe |31, through a coupling member and pressure regulatorvalve |38 which is adjustable 'to reduce the pressure to a requiredlower constant pressure into pipe |39 and an orinc'e |40 of appropriatesize for the operation oi' the meter. From orifice |40 the fluid orwater spills into a drain pipe |4|.

A sleeve |42 providing a connection between orice |40 and pipe |4|V maybe raised for inspection o! the uid flow through the orifice |40 duringoperation of \the meter, but a sealed connection maybe provided betweenpipes |33 and |4| and the fluid may be pumped back into measuringchamber I|4 below diaphragm |23 by means oi a pump |43 connected withpipe |4| -and delivering the fluid through pipe |44 to inlet I|3. Inthis case the pressure regulator |38 and orice |40 may be dispensedwith, and pump |43 is operated to circulate the proper amount oi' tiuidto provide a proper pressure in piston chamber |22 with respect to thepressure in Imeasuring chamber H4.

'I'he piston elements, weight ||8 and tube |24,

are connected through head member |35 with a tubular extension |45passing upwardly through a suitable stuing box in the top of chamber|26, and a lrod |43 is connected with valve element |33 and extendsupwardly concentrically through It determines or cooperates with thepressure in the range tube IIB in determining the mercury levels andthus the position of float |20, and also it passes upwardly through tube|24. through valve member |33 into chamber |26 and out throughregulating valve |38 and ori nce |40 where it spills or to pump |43 andback into inlet ||3. The full pressure of the fluid acts on the lowerside of weight IIB and diaphragm |23 tending to raise them. However the5 fluid pressure and weight IIB in chamber |22 oppose the effect of thefluid pressure under the diaphragm and determine the height weight |I8is raised which height is only suiiicient to permit suilicient passageof water between the rod and its end surface |32 and valve elementdescends oat |20 and valve rod element |21 also descend and more wateris permitted to pass through valve element |33 to increase the iiuldback pressure above the diaphragm and thus the weight descends torestore the balanced condition. Responsive to a rise of the mercury andthe iloat |20 and surface |32 of rod |21 throttles iluid passage throughvalve element |33 decreasing the fluid back pressure above the diaphragmuntil weight IIB is elevated with valve element It 'will be observed ummev ma valve element |11 and.

oat Hl follow the level of mercury ill in the measuring chamber andthese constitute a var.-

` iably movable contact element and the cooperating valve element 4|32constitutes the detector which has been iounri in practiceL to thusfollow the movement of mercury in the measuring chamber with precision.

As just described valve element .In and weight ill move as a unit whichcondition actually exists when mutually locked. It'is obvious, thereforethat external portion of the tubular extension element |45, responds inthe same magnitude yto all changes and indicates all positions oi.' themercury ||9 in chamber ||4, particularly noting that it-is the positionof valve element |34 which determines the indications.

A recorder responding to such movements of tubular rod element |45 plotsor records true mercury positions which are proportional to the squareof the ilowin the usual operation of the meter in measuring uid flow. l

However, yalve element |33 is arranged to slide in bore- |34 whereby aslight movement of this valve element |33 by rodli with respect totubular element |45 extending from the piston elements' is aifordedproviding control mechar 11.` with respecttothe metercasingandextendedls low thereon as desired. As shown theseA levers relation oftheir lengths'as particularly4 defined, Y

the pen arm' can'be directly connected tothe pivot member-these leverelements of course beingof the proper lengths w provide for the maximummovements of the mercury ||5 in measuring chamber ||.4. f

The long levers also provide for smoother operation and opposite pairsmay be spaced in this' type of meter to provide `for operating elementsbetween them. These levers being toggle levers. and having their pivotsin a straight line in their z'ero ition it is essential to apply `anoperating force fr moving them out and into the lzero posinism foroperating control mechanism ||2, comp rising square root levers o f thetype specifically described. These levers, being toggle levers, arepreferably arranged in duplicate pairs on opposite sides of the controlelements, extension tube |45 and rod |46 to compensate for' lateralthrusts. The levers of each pair consist of a lower lever member |41 andan upper lever member |44 comprising respectively levers A and B whichare' mounted reversely of levers A and B as shown in other gures of thedrawings. Lever. elements |48, the B lever elements, are connected bymeans of pivots |49 with the -A lever elements |41, and their upper-ends are connected by pivots |50 to a cross head 5| secured to theupper end of rod |46 and thereby effect movement oi' valve element v|33in following the surface level of mercury ||9 in measuring chamber ||4in the manner already described.

The connection between cross head |5| and rod |46 consists of a tubularextension |52 secured to the cross head and threaded at its upper end.Anadiusting screw |53 on the threaded end of extension |52 is secured bymeans of a set screw |54 to rod |48, but before tightening this setscrew rough adjustments of v alve element |33 carried by rod |46 may bemade. After set screw |54 is tightened'adjusting screw |53which ispreferably graduated as a micrometer, may be turned, with the rod andvalve element, on threaded extension |52 for a close adjustment andaccurate positioning of valve element |33 and for calibration purposes.

The derivation from the operation as described is thatweight ||B andother piston elements moving therewith have a slight relative movementwith respect to valve element |33..

While they are arranged to follow the movement of valve element |33 veryclosely, the slight movement f the piston elements with respect to thevalve element adapts the piston element through their tubularextension|45 in the actuation of the operating mechanism ||2 inobtaining a function ofthe movements of the mercury float as will be setforth. l

The arrangement is such that long vlevers may be employed to advantageas will be seen, with the lower ends of the A lever elements |41 fixedtion. The piston elements perform this function, not only at zero butthroughout the range of the instrument. 'I-'he piston elements inchamber |22 afford a powerful operating element for the up-f wardlyextending tubular element |45 and outside of casing |22 this tube |45carries a crossyhead |58which is in turn connected by links |59 atopposite sides to the square rqpt levers. As shown, links |59 areconnected by pivots |60 to vcrosshead |55 `and by pivots' |5| to the Alever elements m, their length and other relations `-being such thatthere is only a slight relative movement of crossheads |5| and |55 withrespect to each other, yet lever elements ,|41 and links |59 provide aconnection which is capable of thrusting the lever elements outwardly orinwardly in all positions corresponding to the range movement cf themembers whenever there is a change in level of the mercury in themeasuring chamber ||4 which changes the balanced position of the pistonelements backed by the power of the pressures in the measuring andpiston chambers to effect the piston movement which is transmittedthrough crosshead |58 and links |58 to the square root levers. Thusvalve member |33 is so positioned due to the square root lever effectthat while it faithfully follows the rvarying mercury positions thepivots |55 are positioned exactly in agreement with the square root ofthis valve element position.

This meter as set forth is a powerful operat ing instrument particularlyin moving the piston in its upward direction but due to stumlng boxfriction and the various driving operations between the piston elementand levers, if the meter is to be employed for performing operationssuch as variably actua/ting control valves and the like' itmay bedesirable to employ a heavier piston weight element or as 'showncrosshead |55 may be inthe form of an added weight which is effectivevto increase the power of the meter. To facilitate calibration and inchecking the zero position of the lever elements each pair of levers maybe provided with stop element |62 which stops may be individuallyadjusted to proper positions for engagements with the sides of crosshead|58 so that the zero position of the levers can be fixed and departurestherefrom detected.

It is to be observed that throughout-the range ter at all rangesincluding zero and maximum.

However the operation is improved by employing spring elements, such forexample as a compression type of spring |63 surrounding rod |46 andpositioned between crossheads 51| and |58. Althou'gh this spring isunder slightly greater compression at the lower and upper limitsl ofrange it facilitates operation both into and out oi both of these rangepositions without altering or effecting the meter indications withrespect to the positions of float |20. Further the spring actuallyimproves the meter operation by always maintaining all the pivotconnections of the lever members under stress and thereby prevents anyvariations of meter indications which might occur due to variations infit of the pivots so that expensive pivot adjusting elements are notrequired and variations dueto wear of these connections over longperiods will not affect the accuracy of the meter.

In metering practice heretofore the use of cams for converting suchpressure differentials as occur in manometers of the type describedherein and other variable iiuid heights or variable movable membersinto` proportional fiow measurements has been impractical for precisionmeasurements. The rise of a cum at either low or high ranges is toosteep for the operation of a follower directly moved by the cam. Thisdifficulty has been overcome in accordance with the present invention by(1) driving through the levers A and B which are in a straight line atzero position by means of the motor driven arm 63 (Fig. 1), and (2) inoperating through cam mechanism of the circular or roller type describedherein or the` aligned A and B lever elements which are equivalentthereof in this respect bymeans of operating mechanism (Fig. 10) whereinthe actuation of the levers is effected through extension tube member|45 and associated parts as controlled by rod |46 which followsthemovement of the variably movable member or fluid rises with precislon.

I do not wish to limit myself to any of the spe-4 ciiic constructions,measurements or modes of op.. eration described above in thisspecification for purpose of giving examples or illustrations ofemployment of the invention, for it will be obvious that wide departurefrom the above may be made without departing from the spirit and scopeofmy invention which is as set forth in the following claims.

I claim:

l. A meter including an indicator, a movable contact element variablewith a quantity to be measured, a detector for cooperating with saidcontact, power operating means for moving the indicator limited by themovement of the detector, and interacting operating means between saidpower means and the detector for squaring the motion of the indicatorand operating the `detector in accordance with said squared movement. Y

2. A meter including an indicator, a movable contact element variablewith a quantityy to be measured, a detector for cooperating with saidcontact, power operated means for moving the indicator limited by themovement of the detector, interacting operating means between said powermeans and the detector for squaringthe motion of the indicator andoperating the detector in accordance with said squared movement, andmeans for moving the detector beyond the range of movement of themovable contact without moving the indicator.

3. A flow meter including an indicator, a movable contact elementvariable with the flow differential pressures of a quantity to bemeasured, a detector for cooperating with said ccntact, a pair of leverelements coacting between the indicator and detector for controlling themovements thereof so that when the detector is moved in proportion tothe differential pressure of the quantity the indicator will be movedsubstantially in linear proportion to the flow o! the quantity, powermeans for operating the indicator directly and the detector through saidlever elements, and means for controlling the operation of the indicatorby the power means in accordance with the positions of the `movablecontact element as determined by the detector.

4. A meter for indicating a function of a quantity including,-a contactvariably movable in accordance with the quantity to be measured. areciprocatory detector cooperating with said movable contact, drivingmeans for operating said detector in either direction, an operatingconnection associated with the driving means and said detector foroperating an indicator, time controlled means for effecting movement ofthe detector in one direction by said driving means, and means to effecta reversed movement of the detector by said driving means when thedetector breaks contact with the movabie con-l tact.

5. A meter including an indicator for indicating a function of aquantity to be measured, a fluid column movable responsive to thequantity, a detector cooperating therewith to detect movements of theiiuid column, operating means for reciprocably moving the detector andeffecting indications of the indicator, a reversible motor operable todrive the operating means through aforward movement of the detector, andmeans for reversing the drive of said motor at the instant the detectorbreaks contact with the fluid column for effecting a return of thedetector to its initial lowermost position in the fluid column.

6. A meter including an indicator for indieating a function of aquantity to be measured, a fluid column movable responsive to thequantity, 'a detector cooperating therewith to detect movements of thefluid column, operating means for reciprocably moving the detector andeffecting indications of the indicator, a. reversible motor operable todrive the operating means through a forward movement of the detector,means for reversing the drive of said motor at the instant the detectorbreaks contact with the uld column for effecting a return of thedetector toits initial position in the fluid column, and means forinitiating driving operations of the motor for forward movements of thedetector at timed intervals.

7. A meter including a contact variably movable in accordance with aquantity to be measured, a detector contact reciprocable with respect tosaid variably movable contact, an eiement for indicating a function ofthe quantity to be measured, and means for moving the' in- 9. A meterfor indicating a function of a quantity represented by movements of afluid, including the combination with a reciprocatory detector element,of means for adjusting the relation of the fluid and detector withrespect to each other, and an element for coacting with the detectortemporarily displacing the detector to effect an artificial indicationof the meter during an adjustment forcalibration thereof.

10. A meter for indicating a function of a quantity represented bymovements of a fluid in a manometer or the like, including thecombination with a detector member coacting with respect to the fluid inthe manometer, of a. fluid flow control member in the manometer, andmeans to periodically operate said control member for controlling theflow of the fluid in said manometer.

11. In a meter for indicating a function of a quantity represented bythe movement of a fluid column, a detector member coacting therewith andmovable into and out of the fluid column, and a thermal elementconnected w'th the detector tovary its position to compens te forexpansion and contraction affecting the relation f the detector withrespect to the fluid column due to temperature variations.

12. In a meter for indicating a function of a quantity represented bymovements of mercury in a manometer or the like, said manometercharacterized by having a part of its internal surface amalgamated so asto lprovide a uniform meniscus of the mercury at its surface in themeasuring chamber and substantially frictionless travel of -the mercurythrough the manometer as it is displaced subject to varying forcesacting on it effecting movement thereof to be detected, and meanscooperating with the mercury in the manometer for detecting movementsthereof.

13. A meter including a movable fluid column, a detector cooperatingtherewith to detect movements of the fluid column by breaking contacttherewith, means for reciprocating said detector in the fluid column,and stabilizing means for effecting a constant and uniform formation ofthe fluid surface vat the time the detector breaks contact therewithcomprising a displacer reciprocated with the detector in the fluidcolumn being withdrawn therefrom ahead of the time the detector breakscontact with the column.

14. A meter including an indicator. a fluid Y.

-column and effecting operations of the indicator,

and stabilizing means for effecting a constant and uniform formation ofthe fluid surface at the time of detection thereof, including a floatcentrally positioned on the fluid column and a displacer cooperatingwith the detector to produce a relative movement of the fluid withrespect to the detector.

l5. In ameter for indicating a function of a quantity represented by themovement of a fluid column, a detector member coacting therewith andmovable into and out of the fluid column, and a fluid displacer attachedto and coacting with the detector so as to reciprocably move with thedetector into and out of the fluid column during the operation ofthe'meter.

16. In a meter for indicating a function of a quantity represented bymovements of an electrically conductive fluid in a column or the like,

a detector element cooperable with the fluid for' detection of movementsthereof by breaking electrical contact With'the surface of the fluid,operating means associated therewith for effecting indications of themeter, and a float carried by the fluid having a bore through which saiddetector element can freely cooperate with the ,fluid for electricalcontact directly with the fluid in the column.

17. In av meter for indicating a function of a quantity represented bymovements of mercury in a column or the like, an element cooperable withthe mercury for detection of movements thereof, operating meansassociated therewith for effecting indications of the meter, and a floatcarried by the mercury having a bore through which said detector elementcan freely cooperate with the mercury for electrical contact direct withthe mercury in the column, said float characterized by having a. part ofits surface amalgamated so as to form a stable meniscus at thecontacting point.

18. In a meter for indicating a function of a quantity represented bymovements of a fluidv column, a detector, operating means associatedwith the detector for reciprocating it and effecting indications of themeter, a member in the form of a float movable in accordance with thequantity being metered, said member having a well therein for retainingfluid constituting a fluid column in which the detector is reciprocablymoved by said operating means, and means for determining the length ofsuch reciprocations in the fluid column by the breaking of the contactof the detector withA the column.

19. A flow meter including an indicator, a fluid chamber having a fluidcolumn therein variable with the flow differential pressures of a.quantity to be measured, a float on said column movable therewith, poweroperating mechanism including an operating piston, means for controllingthe fluid flow from said chamber responsive to variations in the heightof the fluid column for controlling the operation of said piston, saidcontrol means comprising valve means controlled by the float forpermitting a discharge of fluid from the chamber for controlling thepressure acting on the piston for effecting movement of the piston,interconnected operating means between said valve means and theindicator whereby the indicator will be moved directly in proportionwith the fluid flow of the quantity being measured. and a connectionbetween the interconnected operating means and said operating pistonwhereby the piston will have a movement varying from the movement of thefluid column by the fluid pressure acting on it but is operable to movethe Valve means directly in accordance with the movement of the fluidcolumn so that the indicator will give flow indications correspondingwith the flow of the quantity being measured.

20. A meter including an indicator, a member variabLv movable with afunction of a value to be measured, operating mechanism including a'yiluid chamber with a co-extensive piston chamber. a weight outside ofsaid chambers for operating the indicator in one direction. a pistonweight within the piston chamber cooperating with the weight outside ofsaid chambers, a diaphragm connected w said sind chamber and supportingsaid weights so that a portion thereo! supporting said weights` may bevariably moved with respect to the chamber, means for admitting pressureto said diaphragm for moving both of said weights and the indicator inthe other direction, valve means controlled in accordance with themovement of the variably movable member for controlling the pressureacting on the 'diaphragm for effecting movement thereof in accordancewith the movement of the variably movable member, and inter-connectedoperating means between the weights and valven means for controlling theposition of the valve means in cooperation with the movement of thevariably movable member.

21. An instrument having in combination a fluid pressure chamber andmovable piston meansin said chamber acted upon by iluid pressuregtherein. said piston means dividing said chamber into two pressurecompartments, means for admitting iiuid pressure into one oi' saidcompartments, a variable oriiice connecting the latter with the secondcompartment, a fixed orifice in the second compartment, a fluidregulator in communication between the second compartment and said xedorifice to maintain a uniform duid pressure on the orice, a memberresponsive to variations in the value to be measured for controlling theeffective area oi' said variable oriiice thereby varying the pressuresacting on said piston means, and an indicator operated by said pistonmeans as it moves in response to the variable pressure exerted thereon.

22. An instrument having incombination a fluid pressure chamber andmovable piston means in said chamber acted upon by uid pressurestherein, said piston means dividing said chamber into two pressurecompartments, means for admitting fluid pressure into one of saidcompartments, a variable orice connecting the latter with the secondcompartment, a pump connected between said compartments operable tocontinuously withdrawn a predetermined quantity oi' iluid from thesecond compartment and return it to the tlrst compartment to maintain afixed relation of pressures on opposite sides of the piston means whenthe piston means is positioned in accordance with the quantity beingmeasured, a member responsive to variations in the value to be measuredfor controlling the edective area of said variable oriilce therebyvarying the pressures acting on said piston means. and an indicatoroperated by said piston means as it moves in response to the variablepressures exerted thereon.

23. In a iiow meter including an indicator, a member variably movable inresponse to differential pressures resulting from the iiow`of a quantityto be measured, a detector for cooperation therewith. interacting meansassociated with the detector and indicator'for eii'ecting movement mentvof the variably movable member and moving the indicator directlyproportional to the iiow of the quantity being measured. and power meanscontrolled by movement oi' the variably movable member in cooperation`with the de- 'tector for eecting the actuation of said interacting meansand thereby through the interacting means eiecting the correspondingmovements ox' the indicator and detector.

24. A meter'i'or measuring the position ola movable member, including anindicator and a detector ior cooperating with the movable member, a pairoi lever elements' providing coacting means between the detector and`the indicator, power means for operably moving the lever elements withrespect to each other in accordance with movements of the movable membercontinuously controlling the movement of the lever elements throughoutthe range of the meter during the operation thereof. said power meansfor moving the lever elements including avrotary driving elementoperable on one of the lever elements for moving both lever elements inaccordance with all positions of the movable member and means forcontrolling said power means in accordance with movements of thedetector with respect to the movable member.

25. A meter i'or measuring the position of a movable member fol a rangeof movement from a zero position to a determined maximum, said meterincluding a detector for cooperating with the movable member and anindicator for indicating a function of the movement of the movablemember, means for operating said indicator to indicate the function ofthe movement of the movable member including a pair of coacting leverelements between the indicator and detector, said lever elementsconnected for movement from a straight line position to any buckledposition with respect to each other incident to the movements of themovable member, power means acting on said lever elements for operablymoving them into and out of various positions with respect to each otherto positions corresponding to the positions of the movable member,

' and means for controlling `the actuation oi sa'id lever elements bysaid power operated means in accordance with they position of themovable member in cooperation with the detector throughout the entirerange of the meter.

26. A meter for measuring movements ot a movable member from a zeroposition `throughout its range oi' movement, including indicating means,detecting means for detecting movements ot the movable member, actuatingmeans for moving the detector in accordance with movements of themovable member and for moving the indicator with modified movements withrespect to movements of the movable member, power'means for operatingsaid detector and indicator actuating means throughout the entire rangeof the meter, means for controlling said power means in accordance withthe positions oi' the movable member as determined by the deoi' thedetector in accordance with the move- 75 tector, and means operated bythe power means to give the detector an additional movement below thezero position of the movable member.

27. A meter for measuring the position o! a movable member including anindicator for indicating functions of movements and a detector fordetecting positions of the movable member, interacting means between theindicator and detector comprising a pair of coacting lever elementsarranged in a straight line in 'the zero range position oi' the movablemember 4and in angular positions with respect to each othercorresponding to movements of the movable member from the zero rangeposition. power means continually operable on said lever elements tomove them from their straight line zero position and to all otherpositions of th lever elements with respect to each other throughout therange of the meter during the operation thereof, and means forcontrolling said power means in accordance with the position of themovable member as determined by the detector.

28. A meter for measuring the position of a movable member including anindicator for indicating functions of movements and a detector fordetecting positions of the movable member, and interacting means betweenthe indicator and detector comprising a pair of lever elements one ofwhich lever elements has a circular contact surface whose center islocated at a predetermined distance from the pivoting point of thelever, and the other of which lever elements also includes a circularcontact surface for coacting with the circular contact surface of thefirst said lever element.

29. A meter for measuring a function of a quantity represented bymovements of mercury,

including an indicator, a manometer comprising a measuring chamber and arange'tube communicating therewith, said manometer characterized byhaving a part of its internal surface including its range tubeamalgamated so as to provide a uniform meniscus of the mercury at itssurface in the measuring chamber and substantialLv frictionless travelof the mercury through the manometer as lit is displaced subject tovarying forces acting on it effecting movement thereof to be detected,said manometer having mercury therein and a float on the mercury in themeasuring chamber, and interacting means between the float in themeasuring chamber and the indicator operable on the indicator to eil'ectindications thereof corresponding with the positions of the mercury inthe measuring chamber of the manometer.

30. A meter including an indicator for indicating a function of aquantity to be measured, a contact movable in accordance with thequantity to be measured, a detector for cooperating with said movablecontact, inter-operating means between the indicator and detector'whereby when the indicator is moved the detector will be moved inaccordance with the square of the movement of the indicator, electricpower operating means for actuating the indicator and translatingmovement through said inter-operating means between the indicator anddetector for operating the detector with a corresponding functionalmovement, and means for controlling the operation of the indicator bysaid electric power means in accordance with movements of the movablecontact as determined by the detector.

31. A meter including an indicator for indicating flow measurementsrepresented by differential pressures of a quantity to be measured, acontact movable in accordance with the quantity to be measured, adetector for cooperating with said movable contact, inter-operatingmeans between the indicator and detector whereby when the indicator ismoved the detector will be moved in accordance with a function of themovement of the indicator, said interoperating means including a pair oflever elements coacting between the indicator and detector forcontrolling the movements thereof so that when the detector g is movedin proportion to the dierential pressure 4a corresponding functionalmovement,

of the quantity the indicator will be moved substantially in linearproportion kto the flow of the quantity, power operating means foractuating the indicator and translating movement through saidinteroperating means between the indicator and detector for operatingthe detector with and means for controlling the operation of theindicator by said power means in accordance with movements of themovable contact as determined by the detector.

32. The combination in a meter including an indicator, a contact movablein accordance with a quantity to be measured, and a detectorreciprocably movable for cooperating with said movable contact, ofinter-operating means between the indicatorand detector operable totranslate progressive movements of the indicator into movementsfunctionally related thereto in accordance with an exponential power formoving the detector, power operating means appliedto the indicator endof the inter-operating means for driving said inter-operating meansadapted to operate the indicator directly therewith and translatemovement through said interoperating means for driving the detectorimparting exponential functionally related movements thereto, and meansfor controlling the movements of the indicator by the power operatingmeansiin accordance with the positions of the movable contact member asdetermined by the detector.

33. 'I'he combination in a` meter including an indicator. a contactmovable in accordance with a quantity to be measured. and a detectorreciprocably movable for cooperating with said movable contact, ofinter-operating means between the indicator and detectorv comprising apair of coacting lever elements such as a pair of coacting cams, one ofwhich lever elements is mounted for angular movement about a fixed pivotaxis and with which the indicator is associated, and the other of whichlever elements coacting with the first lever element has a connectionwith the detector for reciprocably moving it, power means for drivingthe first lever element and adapted to operate the indicator directlytherewith and to therebyA drive the detector connected with the secondcoacting lever element, and means for controlling the movements of theindicator by the power means in accordance with the positions of themovable contact as determined by the detector.

34. In a meter for indicating a function of a fluid quantity to bemeasured represented by movements of a mercury iiuid column as affectedby said uid quantity, a detector having a contact tip at its lower end,operating means associated with the detector for verticallyreciproeating it'in said fluid column and effecting indications of themeter, means for determining the length of such reciprocations in theuid column by the breaking of contact of the detector tip with thecolumn, and shielding means on the detector above the contact tiplimiting the amalgamable area of the contact tip mid detector having itscontact tip amalgamated whereby continuous breaking contact with themercury in the column can be had lwith precision accuracy of themeasurements of such breaks.

35.111 a meter for indicating a function of a uid quantity to bemeasured represented by movements of a mercury iiuid column as affectedby said fluid quantity, a detector having a contact tip at its lowerend, operating means associated with the detector for verticallyreciprocting it in said fluid column and eiecting indications uf'themeter, means for determining the lenlth of luch reciprocations in thefluid coiumn by the breaking of contact of the detector tip with thecolumn1 said detector having its 'contact tipA amalgamad wherebycontinuous breaking contact with the mercury in the column can bevindwith precision accuracy of the measurements of such breaks, shieldingmeans on the lo PAUL

